Polyurethane foam compositions are typically prepared by reacting an isocyanate and a premix which consists of isocyanate-reactive components such as a polyol. The premix optionally also contains other components such as water, flame retardants, blowing agents, foam-stabilizing surfactants, and catalysts to promote the reactions of isocyanate with polyol to make urethane, with water to make CO2 and urea, and with excess isocyanate to make isocyanurate (trimer). The blowing agent in the premix is usually a liquid or gas with a boiling point sufficiently low to be vaporized by the heat released during the polymerization reaction. Examples of blowing agents useful in the production of insulating polyurethane foam include but are not limited to hydrofluorocarbons, hydrochlorocarbons, hydrofluoroolefins, hydrochloroolefins, hydrofluorochloroolefins, hydrochlorofluorocarbons, formates, and hydrocarbons. The proper selection and combination of the components in the premix and the isocyanate can be useful for the production of polyurethane foam that is spray applied, poured in place, and used in applications such as refrigerators, freezers, hot water heaters, insulation panels, garage doors, entry doors, and other various applications where insulation is desired. For some of these applications, the premix is stored for one day up to one year before being reacted with isocyanate to generate polyurethane foam. This is common in spray foam applications, where drums of premix and isocyanate are shipped to field locations for on-site application. Thus, it is desirable for the premix of an insulating foam formulation to be both chemically and physically stable. However, in some cases, the catalysts that are useful to promote the polyurethane reaction can also participate or induce undesired hydrolysis reactions with the blowing agents, polyether polyols, flame retardants or other hydrolytically unstable components present in the premix resulting in reduced storage stability. These undesired reactions are typically observed in spray foam systems containing polyester polyol as well as spray foam systems containing halogenated components that can act as flame retardants or blowing agent.
Common amine catalysts useful for the production of polyurethane foam include tertiary amines which are known to accelerate the urethane reaction promoting the formation of polyurethane polymers. However, in some cases, tertiary amines can catalyze the hydrolysis of esters causing the formation of carboxylic acids which in turn can neutralized the tertiary amine catalysts in the systems causing a slowdown in the reactivity of the mixture towards isocyanate. This reactivity slowdown can also result in various quality issues such as sagging during spray foam applications and it can also produce polyurethane foam with poor physical properties.
JP 2007077240 describes a conventional catalyst composition comprising ANR1R2 (A=C8-18 alkyl; R1, R2=C1-6 alkyl) and tertiary amines having hydroxyalkyl group in a mol. WO 2005030824 describes a catalyst composition comprising (A) quaternary ammonium compounds. R1R2R3N+R4X—, (B) hydrophobic amine compounds, and/or (C) heterocyclic tert-amine compounds, polyol components, and water, wherein R1, R2, R3=C1-12 hydrocarbon; R4=C1-18 alkyl or aromatic hydrocarbon; and X=organic acid group with acid dissociation constant (pKa)≤4.8.
JP 2004292582 discloses catalysts comprising quaternary ammonium compound salts (NR1R2R3R4)+HCO3- or (NR1R2R3R4)+2CO32- (R1-R3=C1-12 hydrocarbon group; R4=C1-18 linear saturated hydrocarbon group, 2 of R1-R3 may form a hetero ring via C, O, or N).
JP 2001172355 describes a storage stable polyester polyols (OH value >130 and ≤320 mg KOH/g, pH 7-12) prepared by addition polymerization of 38-240 parts epoxides with 100 parts bis(2-hydroxyethyl) terephthalate (BHET) in the presence of basic catalysts at 70-140°.
U.S. Pat. Nos. 5,302,303; 5,374,486 and 5,124,367 describe the use of fatty amido-amines as a component necessary for the stabilization of isocyanate compositions containing flame retardants. The patent describes that the shelf-life stability of isocyanate-reactive compositions, is often adversely affected by the addition of flame retardants, especially those based on phosphorous, zinc, antimony and aluminum.
The disclosure of the previously identified patents are hereby incorporated by reference.
The instant invention can solve problems associated with conventional foam precursors by permitting the use of tertiary amines as described in this invention thereby improving the storage stability of isocyanate reactive mixture containing polyester polyols. The catalyst can also be use in flexible foam applications to produce polyurethane products with low emissions or no amine emissions. A process, a polyurethane composition, a polyurethane product, a process of producing a catalyst composition, and a catalyst that do not suffer from one or more of the above drawbacks would be desirable in the art.